I have just recetly setup a planted 20g high, and I added 3 Panda Cory's after 8 days (not sure if that was a good idea) I also have a Zebra snail in there.

I wanted to get:
4 male Guppies
1 albino (highfin) Bristlenose Pleco
10 Neon Tetras or 6 Black Neon Tetras
and 3-6 Panda Corys, I know this is kinda crowded but I wanted to have fish at all levels of the tank, and I need an algae eater and I heard Bristlenose Plecos are great for that.

I was wondering if it's better to stick with three Panda Corys or six, I know they like others of their species around but is three OK?

In my opinion I'd skip the guppies - they're nasty little carriers of disease that are prone to dying for no good reason now. Possibly due to too much dodgy breeding going on at the fish farms.

Three corys is do-able, but five or seven would be better if that helps...they seem to do better in odd numbered groups for some strange reason. If you're unsure, start out with three. You can always add a couple more later down the track._________________Fishing in the Rivers of Light